Modern travel confirmations (receipts, boarding passes) are often accompanied nowadays by a barcode, which can be used to conduct transactions with the supplier issuing the confirmations. For example, it has become standard for airlines to include a barcode on boarding passes. The airline barcode includes relevant passenger and itinerary data, and the barcode is used to initiate transactions at kiosks equipped with barcode readers, as well as at agent positions such as the boarding gate door.
Although machine readable travel information is efficient for suppliers, the proliferation of bar coded documents can easily become a burden on the traveler. For instance, a typical round trip overnight journey can easily include two airline boarding passes (one for outbound and one for return), a car rental confirmation, and a hotel confirmation. Barcodes on each of these documents contain different data and barcode formats are generally not interoperable between travel suppliers (i.e. between airlines) let alone between different segments of the travel landscape (i.e. between airlines and hotels).